watchRun issue with latest version

[tborychowski]

I updated svelte-loader to the latest version

{
    "svelte": "^2.5.0",
    "svelte-loader": "^2.9.0"
}

and now I'm getting this issue:

[Error running Gulp] Error: ./client/app/index.html
Module build failed: TypeError: Cannot read property 'watchRun' of undefined
    at new VirtualModulesPlugin (/Users/me/project1/node_modules/svelte-loader/lib/virtual.js:35:17)
    at Object.module.exports (/Users/me/project1/node_modules/svelte-loader/index.js:83:46)
 @ ./client/index.js 1:0-24

Edit: this seems to be an issue with the svelte-loader only. When I downgrade to v2.8.1 - everything works.

[perifer]

Looking at the referenced https://github.com/sysgears/webpack-virtual-modules they do this:

    var watchRunHook = function(watcher, callback) {
        self._watcher = watcher.compiler || watcher;
        callback();
    }

    if (compiler.hooks) {
        compiler.hooks.watchRun.tapAsync('VirtualModulesPlugin', watchRunHook);
    } else {
        compiler.plugin("watch-run", watchRunHook);
    }

My very limited understanding of this from reading through the commits of the above repo is that compiler.hooks is for older versions of Webpack.

[SimulatedGREG]

After testing @perifer's comment, I did some more research and found that compiler.hooks were introduced in [email protected], so all previous versions will get the watchRun error. Applying this change with [email protected] fixes the issue.

Given that not everybody may be able to update to v4 just yet, I've made a PR to support older versions. #68

[Rich-Harris]

Fixed in 2.10.1, thanks @SimulatedGREG!